석탄회 성형배지(Ash Ball)의 이화학적 특성과 염류집적 및 제거효과

초록

Physical and chemical properties, the salt accumulation and leaching of salt by water of coal fly ashball (ash ball) were evaluated in comparison with perlite and granule rockwool (rockwool). Bulk den-sity, particle density, solid phase, and porosity of ash ball were 0.93 g cm-3, 2.29 g cm-3, 40.6%,59.4%, respectively. The bulk density of ash ball was greater, while porosity was smaller, than that ofperlite and rockwool. Saturation moisture capacity was 52% in ash ball, 71% in perlite, and 90% inrockwool. Water contents after drainage for 1 hr of ash ball, perlite, and rockwool were 21%, 27%,and 80%, respectively. Water content of small granules (3-5 mm) of ash ball was 5% greater than thatof large (7-15 mm) granules. The ash ball was a weak alkali substrate with pH 7.6, but not electricconductivity (EC), of the nutrient solution supplied to ash ball slightly increased. When the absorp-tion of mineral ions to substrates were analyzed, ash ball and RW absorbed mainly PO4-. In tomatoculture, salt accumulation in ash ball substrate was similar to that in perlite. Most of the salts in theash balls were removed by submerging the substrate eight times in distilled water. It is concluded thatwater holding capacity of ash ball substrate was low as compared to other substrates, but air perme-ability, and water diffusion was excellent, making control of medium water content easy.

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